The ploidy of parts (D) and (E) are:

The correct answer is Option (3) → (D) -n          (E) -n

D and E are cells of the embryo sac at the micropylar end (the egg apparatus). The embryo sac develops from a haploid megaspore by mitosis, so all its cells are haploid (n).

Option (1) (D) -n          (E) -2n — Incorrect. E is a cell of the embryo sac, so it is haploid, not 2n.

Option (2) (D) -2n         (E) -n — Incorrect. D is a cell of the embryo sac, which is formed by mitosis from a haploid megaspore. So D is n, not 2n; no cell of the embryo sac is diploid before fertilisation.

Option (3) (D) -n          (E) -n — Correct. (D) and (E) are cells of the embryo sac, the female gametophyte. All the cells of the gametophyte (egg, synergids, antipodals) are formed by mitosis from a haploid megaspore, so they are haploid (n).

Option (4) (D) -n          (E) -3n — Incorrect. Only the primary endosperm nucleus is 3n, formed after triple fusion.